In the field of odontotherapy were so far developed various types of denture attachments using magnetic attractive force to readily attach and detach a denture, an example of which is disclosed in Patent Reference 1. Conventionally, the denture attachment includes a magnetic device provided in a denture base to which the denture is fixed and exerting magnetic attractive force, and a keeper provided in an abutment (remaining teeth or implant) and made of a soft magnetic material.